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Full-Text Articles in Engineering
A Multicellular Model For Differential Regulation Of Circadian Signals In The Core And Shell Regions Of The Suprachiasmatic Nucleus, Christina Vasalou, Michael A. Henson
A Multicellular Model For Differential Regulation Of Circadian Signals In The Core And Shell Regions Of The Suprachiasmatic Nucleus, Christina Vasalou, Michael A. Henson
Michael A Henson
We developed a multicellular model of the mammalian circadian clock characterized by a high degree of heterogeneity with respect to single cell periodicity and behavior (intrinsic and driven oscillators), neurotransmitter release (VIP, GABA and glutamate synthesis) and spatial organization (core and shell regions), mimicking structural patterns within the SCN associated with distinct circadian functions. We simulated the SCN core and shell separately utilizing experimentally derived connectivity schemes for the two subdivisions as observed within the rat SCN. The core was modeled via a small world network characterized by VIP and GABA colocalization, whereas the shell was simulated as a nearest …
Identification And Thermochemical Analysis Of High-Lignin Feedstocks For Biofuel And Biochemical Production, Venugopal Mendu, Anne E. Harman-Ware, Mark Crocker, Jungho Jae, Jozsef Stork, Samuel Morton, Andrew Placido, George W. Huber, Seth Debolt
Identification And Thermochemical Analysis Of High-Lignin Feedstocks For Biofuel And Biochemical Production, Venugopal Mendu, Anne E. Harman-Ware, Mark Crocker, Jungho Jae, Jozsef Stork, Samuel Morton, Andrew Placido, George W. Huber, Seth Debolt
George W. Huber
Background - Lignin is a highly abundant biopolymer synthesized by plants as a complex component of plant secondary cell walls. Efforts to utilize lignin-based bioproducts are needed. Results - Herein we identify and characterize the composition and pyrolytic deconstruction characteristics of high-lignin feedstocks. Feedstocks displaying the highest levels of lignin were identified as drupe endocarp biomass arising as agricultural waste from horticultural crops. By performing pyrolysis coupled to gas chromatography-mass spectrometry, we characterized lignin-derived deconstruction products from endocarp biomass and compared these with switchgrass. By comparing individual pyrolytic products, we document higher amounts of acetic acid, 1-hydroxy-2-propanone, acetone and furfural …
A Methodology To Estimate Capacity Impact Due To Connected Vehicle Technology, Daiheng Ni, Jia Li, Steven Andrews, Haizhong Wang
A Methodology To Estimate Capacity Impact Due To Connected Vehicle Technology, Daiheng Ni, Jia Li, Steven Andrews, Haizhong Wang
Daiheng Ni
Recent development in connected vehicle technology or equivalently vehicular ad hoc networks (VANET) has stimulated tremendous interests among decision makers, practitioners, and researchers due to the potential safety and mobility benefits provided by these technologies. A primary concern regarding the deployment of connected vehicle technology is the degree of market penetration required for effectiveness. This paper proposes a methodology to analyze the benefit of highway capacity gained from connected vehicle technology. To fulfill this purpose, a model incorporating the effects of connected vehicle technology on car following is formulated, building on which a rough estimate of the resulting capacity gain …
A Systematic Method To Evaluate And Develop Renewable Energy Technologies, George W. Huber, A. A. Upadhye, W. Qi
A Systematic Method To Evaluate And Develop Renewable Energy Technologies, George W. Huber, A. A. Upadhye, W. Qi
George W. Huber
No abstract provided.
Effect Of Stress State On Wrinkle Morphology, Derek Breid, Alfred Crosby
Effect Of Stress State On Wrinkle Morphology, Derek Breid, Alfred Crosby
Alfred Crosby
Wrinkles in thin films on soft substrates have been shown to self-organize into topological patterns, providing a possible route towards inexpensive generation of surface microstructure. However, the effect of the magnitude of applied stress in relation to the critical buckling stress, or overstress, on the observed patterns has until this point been neglected experimentally. In this paper, we investigate the effect of overstress using poly(dimethylsiloxane) which has been surface-oxidized with a UV-ozone oxidation technique. Using a swelling-based stress application technique, where the applied swelling stress in the thin film is controlled by changing the concentration of vapor-phase swelling agent (ethanol) …
Blowing Bubbles To Study Living Material, Alfred Crosby, Jennifer J. Mcmanus
Blowing Bubbles To Study Living Material, Alfred Crosby, Jennifer J. Mcmanus
Alfred Crosby
Living materials respond to stresses, or deformation forces, in profound and surprising ways. Bones become weak if they don’t carry weight. Muscles and soft tissues atrophy, or shrink, if exercise is limited. Whether stem cells differentiate into hard or soft tissue can strongly depend on the stresses they experience during growth. Therefore, to promote or direct the growth of healthy tissue—the challenge of tissue engineering—or to limit the growth of unwanted tissue such as cancerous tumors, scientists must understand the stresses that biological materials experience as they grow and live.
Multicompartment And Multigeometry Nanoparticle Assembly, Darrin J. Pochan, Jiahua Zhu, Ke Zhang, Karen L. Wooley, Caroline Miesch, Todd S. Emrick
Multicompartment And Multigeometry Nanoparticle Assembly, Darrin J. Pochan, Jiahua Zhu, Ke Zhang, Karen L. Wooley, Caroline Miesch, Todd S. Emrick
Todd S. Emrick
The directed or dynamic assembly of molecular components in solution is a simple and effective strategy to confine materials in desired geometries and length scales. We use a kinetic control strategy with block copolymer blending to construct complex nanoparticles through the demixing of unlike block copolymers within the same nanoscale particle. Successful nanoparticle construction relies on kinetic trapping of unlike block copolymers into the same nanoparticle with solution processing. Not only can we make nanoparticles with multiple internal compartments of a desired size, but we can also make nanoparticles of hybrid geometries (e.g. a blend of cylindrical and spherical geometries). …
Pegylated Polymers For Medicine: From Conjugation To Self-Assembled Systems, Maisie J. Joralemon, Samantha Mcrae, Todd S. Emrick
Pegylated Polymers For Medicine: From Conjugation To Self-Assembled Systems, Maisie J. Joralemon, Samantha Mcrae, Todd S. Emrick
Todd S. Emrick
Synthetic polymers have transformed society in many areas of science and technology, including recent breakthroughs in medicine. Synthetic polymers now offer unique and versatile platforms for drug delivery, as they can be “bio-tailored” for applications as implants, medical devices, and injectable polymer-drug conjugates. However, while several currently used therapeutic proteins and small molecule drugs have benefited from synthetic polymers, the full potential of polymer-based drug delivery platforms has not yet been realized. This review examines both general advantages and specific cases of synthetic polymers in drug delivery, focusing on PEGylation in the context of polymer architecture, self-assembly, and conjugation techniques …
Mechanical Behavior Of Ultra-Low-Dielectric-Constant Mesoporous Amorphous Silica, Dimitrios Maroudas, M. R. Gungor, J. J. Watkins
Mechanical Behavior Of Ultra-Low-Dielectric-Constant Mesoporous Amorphous Silica, Dimitrios Maroudas, M. R. Gungor, J. J. Watkins
Dimitrios Maroudas
We report results for the dependence of the mechanical properties of ordered mesoporous silica structures on the pore diameter based on molecular-dynamics simulations. We examine structures with spherical pores arranged in a simple cubic lattice and cylindrical pores arranged in a square lattice subjected to uniaxial tension and compression; for the structures with cylindrical pores, both radial and axial loading is studied with respect to the pore orientation. Our analysis provides a unifying explanation to the observed mechanical response based on the mechanical loading effects on the pore wall thickness.
Chemistry Of Furan Conversion Into Aromatics And Olefins Over Hzsm-5: A Model Biomass Conversion Reaction, George W. Huber, Y. Cheng
Chemistry Of Furan Conversion Into Aromatics And Olefins Over Hzsm-5: A Model Biomass Conversion Reaction, George W. Huber, Y. Cheng
George W. Huber
The conversion of furan (a model of cellulosic biomass) over HZSM-5 was investigated in a thermogravimetric analysis–mass spectrometry system, in situ Fourier transform infrared analysis, and in a continuous-flow fixed-bed reactor. Furan adsorbed as oligomers at room temperature with a 1.73 of adsorbed furan/Al ratio. These oligomers were polycyclic aromatic compounds that were converted to CO, CO2, aromatics, and olefins at temperatures from 400 to 600 °C. Aromatics (e.g., benzene, toluene, and naphthalene), oligomer isomers (e.g., benzofuran, 2,2-methylenebisfuran, and benzodioxane), and heavy oxygenates (C12+ oligomers) were identified as intermediates formed inside HZSM-5 at different reaction temperatures. During furan conversion, graphite-type …
Catalytic Conversion Of Biomass-Derived Feedstocks Into Olefins And Aromatics With Zsm-5: The Hydrogen To Carbon Effective Ratio, George W. Huber, H. Zhang, Y. Cheng, T. P. Vispute, R. Xiao
Catalytic Conversion Of Biomass-Derived Feedstocks Into Olefins And Aromatics With Zsm-5: The Hydrogen To Carbon Effective Ratio, George W. Huber, H. Zhang, Y. Cheng, T. P. Vispute, R. Xiao
George W. Huber
Catalytic conversion of ten biomass-derived feedstocks, i.e. glucose, sorbitol, glycerol, tetrahydrofuran, methanol and different hydrogenated bio-oil fractions, with different hydrogen to carbon effective (H/Ceff) ratios was conducted in a gas-phase flow fixed-bed reactor with a ZSM-5 catalyst. The aromatic + olefin yield increases and the coke yield decreases with increasing H/Ceff ratio of the feed. There is an inflection point at a H/Ceff ratio = 1.2, where the aromatic + olefin yield does not increase as rapidly as it does prior to this point. The ratio of olefins to aromatics also increases with increasing H/Ceff ratio. CO and CO2 yields …
Analysis Of Aggregate Size As A Process Variable Affecting Paclitaxel Accumulation In Taxus Suspension Cultures, Martin E. Kolewe, Michael A. Henson, Susan C. Roberts
Analysis Of Aggregate Size As A Process Variable Affecting Paclitaxel Accumulation In Taxus Suspension Cultures, Martin E. Kolewe, Michael A. Henson, Susan C. Roberts
Michael A Henson
Plant cell aggregates have long been implicated in affecting cellular metabolism in suspension culture, yet the rigorous characterization of aggregate size as a process variable and its effect on bioprocess performance has not been demonstrated. Aggregate fractionation and analysis of biomass-associated product is commonly used to assess the effect of aggregation, but we establish that this method is flawed under certain conditions and does not necessarily agree with comprehensive studies of total culture performance. Leveraging recent advances to routinely measure aggregate size distributions, we developed a simple method to manipulate aggregate size and evaluate its effect on the culture as …
Modeling Silicic Acid Polymerization Using A Low Coordination Lattice Model, Peter A. Monson, Scott M. Auerbach, Lin Jin
Modeling Silicic Acid Polymerization Using A Low Coordination Lattice Model, Peter A. Monson, Scott M. Auerbach, Lin Jin
Peter A. Monson
We present an atomic lattice model for studying the polymerization of silicic acid in sol-gel and related processes for synthesizing silica materials. Our model is based on Si and O atoms occupying the sites of a body-centered-cubic lattice, with all atoms arranged in SiO4 tetrahedra. This is the simplest model that allows for variation in the Si–O–Si angle, which is largely responsible for the versatility in silica polymorphs. The model describes the assembly of polymerized silica structures starting from a solution of silicic acid in water at a given concentration and pH. This model can simulate related materials—chalcogenides and clays—by …
Simulating Infrared Spectra And Hydrogen Bonding In Cellulose Iβ At Elevated Temperatures, George W. Huber, V. Agarwal, W. C. Conner Jr.
Simulating Infrared Spectra And Hydrogen Bonding In Cellulose Iβ At Elevated Temperatures, George W. Huber, V. Agarwal, W. C. Conner Jr.
George W. Huber
We have modeled the transformation of cellulose Iβ to a high temperature (550 K) structure, which is considered to be the first step in cellulose pyrolysis. We have performed molecular dynamics simulations at constant pressure using the GROMOS 45a4 united atom forcefield. To test the forcefield, we computed the density, thermal expansion coefficient, total dipole moment, and dielectric constant of cellulose Iβ, finding broad agreement with experimental results. We computed infrared (IR) spectra of cellulose Iβ over the range 300–550 K as a probe of hydrogen bonding. Computed IR spectra were found to agree semi-quantitatively with experiment, especially in the …
Production Of Green Aromatics And Olefins By Catalytic Fast Pyrolysis Of Wood Sawdust, George W. Huber, T. R. Carlson, Y. -T Cheng, J Jae
Production Of Green Aromatics And Olefins By Catalytic Fast Pyrolysis Of Wood Sawdust, George W. Huber, T. R. Carlson, Y. -T Cheng, J Jae
George W. Huber
Catalytic fast pyrolysis of pine wood sawdust and furan (a model biomass compound) with ZSM-5 based catalysts was studied with three different reactors: a bench scale bubbling fluidized bed reactor, a fixed bed reactor and a semi-batch pyroprobe reactor. The highest aromatic yield from sawdust of 14% carbon in the fluidized bed reactor was obtained at low biomass weight hourly space velocities (less than 0.5 h−1) and high temperature (600 °C). Olefins (primarily ethylene and propylene) were also produced with a carbon yield of 5.4% carbon. The biomass weight hourly space velocity and the reactor temperature can be used to …
Production Of Furfural And Carboxylic Acids From Waste Aqueous Hemicellulose Solutions From The Pulp And Paper And Cellulosic Ethanol Industries, George W. Huber, R. Xing, W. Qi
Production Of Furfural And Carboxylic Acids From Waste Aqueous Hemicellulose Solutions From The Pulp And Paper And Cellulosic Ethanol Industries, George W. Huber, R. Xing, W. Qi
George W. Huber
In this paper we present a new process to produce furfural and co-products of formic and acetic acids from waste aqueous hemicellulose solutions using a continuous two zone biphasic reactor. We estimate this approach uses 67% to 80% less energy than the current industrial processes to produce furfural. An economic analysis indicates that furfural can be produced with this process at 366 US$ per metric ton which is 25% of the selling price of furfural in the U.S. market today. This analysis assumes a plant capacity of 78 kiloton per year of furfural, 12 kiloton per year of formic acid …
Aerosol Generation By Reactive Boiling Ejection Of Molten Cellulose, Paul J. Dauenhauer, A. R. Teixeira, K. G. Mooney, J. S. Kruger, C. L. Williams, W. J. Suszynski, L. D. Schmidt, D. P. Schmidt
Aerosol Generation By Reactive Boiling Ejection Of Molten Cellulose, Paul J. Dauenhauer, A. R. Teixeira, K. G. Mooney, J. S. Kruger, C. L. Williams, W. J. Suszynski, L. D. Schmidt, D. P. Schmidt
Paul J. Dauenhauer
The generation of primary aerosols from biomass hinders the production of biofuels by pyrolysis, intensifies the environmental impact of forest fires, and exacerbates the health implications associated with cigarette smoking. High speed photography is utilized to elucidate the ejection mechanism of aerosol particles from thermally decomposing cellulose at the timescale of milliseconds. Fluid modeling, based on first principles, and experimental measurement of the ejection phenomenon supports the proposed mechanism of interfacial gas bubble collapse forming a liquid jet which subsequently fragments to form ejected aerosol particles capable of transporting nonvolatile chemicals. Identification of the bubble-collapse/ejection mechanism of intermediate cellulose confirms …
Renewable Gasoline From Aqueous Phase Hydrodeoxygenation Of Aqueous Sugar Solutions Prepared By Hydrolysis Of Maple Wood, George W. Huber, N. Li, G. A. Tompsett, T. Zhang, J. Shi, C. E. Wyman
Renewable Gasoline From Aqueous Phase Hydrodeoxygenation Of Aqueous Sugar Solutions Prepared By Hydrolysis Of Maple Wood, George W. Huber, N. Li, G. A. Tompsett, T. Zhang, J. Shi, C. E. Wyman
George W. Huber
In this paper we demonstrate an integrated process for the production of high octane gasoline from maple wood by hydrolysis of maple wood into aqueous carbohydrate solutions followed by aqueous phase hydrodeoxygenation of the sugar solutions. The aqueous carbohydrate solutions were prepared by both hydrolysis in hot water and hydrolysis with dilute acids (H2SO4, oxalic acid). The aqueous carbohydrate solutions were a mixture of xylose, water soluble hemicellulose oligomers, acetic acid, glucose, glucose oligomers, and probably some lignin polymers. Hydrolysis with hot water produced primarily hemicellulose oligomers whereas hydrolysis with acids produced mainly xylose and acetic acid. The hydrolysis co-product …
Asymmetry In Chemical Structures And In Life: My Last Two Articles, Otto Vogl
Asymmetry In Chemical Structures And In Life: My Last Two Articles, Otto Vogl
Otto Vogl
No abstract provided.
Room Temperature Magnetic Materials From Nanostructured Diblock Copolymers, Zoha M. Al-Badri, Raghavendra R. Maddikeri, Yongping Zha, Hitesh D. Thaker, Priyanka Dobriyal, Raja Shunmugam, Thomas P. Russell, Gregory N. Tew
Room Temperature Magnetic Materials From Nanostructured Diblock Copolymers, Zoha M. Al-Badri, Raghavendra R. Maddikeri, Yongping Zha, Hitesh D. Thaker, Priyanka Dobriyal, Raja Shunmugam, Thomas P. Russell, Gregory N. Tew
Gregory N. Tew
Nanostructured magnetic materials are important for many advanced applications. Consequently, new methods for their fabrication are critical. However, coupling self-assembly to the generation of magnetic materials in a simple, straight-forward manner has remained elusive. Although several approaches have been considered, most have multiple processing steps, thus diminishing their use of self-assembly to influence magnetic properties. Here we develop novel block copolymers that are preprogrammed with the necessary chemical information to microphase separate and deliver room temperature ferromagnetic properties following a simple heat treatment. The importance of the nanostructured confinement is demonstrated by comparison with the parent homopolymer, which provides only …
Depletion Versus Deflection: How Membrane Bending Can Influence Adhesion, Jin Nam, Maria Santore
Depletion Versus Deflection: How Membrane Bending Can Influence Adhesion, Jin Nam, Maria Santore
Maria Santore
During depletion-driven vesicle adhesion, a stiff membrane’s resistance to bending at fixed tension prevents contact angle equilibrium and vesicle spreading over an opposing vesicle, while more flexible vesicles partially engulf opposing vesicles. Estimates of the bending cost associated with the spreading contact line, relative to the adhesion energy, were consistent with the observed spreading or lack of spreading for the flexible and stiff membranes, respectively, and predicted a lag time sometimes preceding spreading.
Synthesis Of Hydrogels Via Ring-Opening Metathesis Polymerization: Factors Affecting Gelation, Gregory N. Tew, Ahmad E. Madkour, Joshua M. Grolman
Synthesis Of Hydrogels Via Ring-Opening Metathesis Polymerization: Factors Affecting Gelation, Gregory N. Tew, Ahmad E. Madkour, Joshua M. Grolman
Gregory N. Tew
Ring-opening metathesis polymerization (ROMP) was used to synthesize hydrogels via copolymerization of a diamine monomer 3 and a novel cross-linker 5 using Grubbs' third generation catalyst as initiator. Reactions were performed at two different monomer concentrations and at various initial molar ratios of cross-linker to initiator. At low monomer concentration, gelation occurred at initial cross-linker to initiator ratios of 1.5 and greater, which decreased to values of 1.05 and greater when increasing the monomer concentration. This result is in agreement with the Flory–Stockmayer theory. The gel yield and swelling properties were also found to be dependent on the cross-linker to …
Center Of Umass – Industry Research On Polymers: Cumirp: Inception And Founding, Otto Vogl
Center Of Umass – Industry Research On Polymers: Cumirp: Inception And Founding, Otto Vogl
Otto Vogl
No abstract provided.
Polymer Science And The Arts: Oriental Lacquer, Otto Vogl
Polymer Science And The Arts: Oriental Lacquer, Otto Vogl
Otto Vogl
No abstract provided.
Cavitation Rheology Of The Eye Lens, Alfred Crosby, Jun Cui, Cheol Hee Lee, Aline Delbos, Jennifer J. Mcmanus
Cavitation Rheology Of The Eye Lens, Alfred Crosby, Jun Cui, Cheol Hee Lee, Aline Delbos, Jennifer J. Mcmanus
Alfred Crosby
The anisotropic mechanical properties of bovine eye lenses were measured using cavitation rheology over a range of length scales. The technique involves inducing a cavity at the tip of a syringe needle in different regions of the lens. Effective Young's moduli of the nucleus and cortex of the lens were determined, as approximately 11.8 and 0.8 kPa, respectively, on macroscopic length scales. We also measured the mechanical properties of the lens on the length scale of a single cell, suggesting that the stiffness significantly decreased from that in the bulk measurements for both the nucleus and cortex. In addition, during …
Multiscale Modeling Of Traffic Flow, Daiheng Ni
Multiscale Modeling Of Traffic Flow, Daiheng Ni
Daiheng Ni
This paper presents a broad perspective on traffic flow modeling at a spectrum of four scales. Modeling objective and model properties at each scale are discussed and existing efforts are reviewed. In order to ensure modeling consistency and provide a microscopic basis for macroscopic models, it is critical to address the coupling among models at different scales, i.e. how less detailed models are derived from more detailed models and, conversely, how more detailed models are aggregated to less detailed models. With this understanding, a consistent modeling approach is proposed based on field theory and modeling strategies at each of the …